This study explores the use of Total Marrow and Lymphoid Irradiation (TMLI) as a new method to prepare patients for a special type of stem cell transplant. It might be safer than the older method, Total Body Irradiation (TBI), which can have long-term side effects. The study targets patients aged 16 to 45 with a type of blood cancer called Acute Lymphoblastic Leukemia (ALL). The procedure involves several medications and a special type of radiation before receiving the stem cells.

If you join this study, you'll receive Fludarabine and Cyclophosphamide for several days, and possibly TMLI radiation for the last three days before the stem cell transplant. The whole process is carefully monitored, including bone marrow checks after 60 days.

• The study lasts at least 60 days post-transplant.
• There are criteria like age and health requirements to join.
• Special medical follow-up is required during and after the study.